Heat sink and method of manufacture thereof

ABSTRACT

In a first process of this method of manufacturing a heat sink, into a groove, formed in a base and both of whose side surfaces are provided with projections or concave portions and whose upper portion is open, from the groove open portion, there is fitted a pipe that has a diameter smaller than the gap between the edge portions of the open portion of the groove. Next, the pipe is pressed from above the open portion of the groove and the upper portion of the pipe is deformed so that it follows the plane of the open portion of the groove, and moreover both side portions of the pipe are deformed so that they follow along the inner surfaces of both side portions of the groove. By this second process, both side portions of the pipe are engaged with the projections or concave portions.

CROSS REFERENCE

This Nonprovisional application claims priority under 35 U.S.C. §119(a)on Patent Application No. 2009-148449 filed in Japan on Jun. 23, 2009,the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a heat sink that cools a thermalcomponent, and to a method of manufacturing such a heat sink.

Sometimes a radiator type heat sink is used for cooling a thermalcomponent such as a semiconductor or the like. As this type of heatsink, for example, in the base of the heat sink, its upper portion maybe formed by opening up channels (grooves) therein. These channels mayhave tapers, so that the gaps at the end portions at which they areopened are smaller than the gaps at the bottom portions of the channels.A structure for cooling a thermal component is disclosed in JapanesePatent Publication 11-510962 in which pipes are pressed into thesechannels and are deformed into almost the same flat plane as the basesurface, and the thermal component is cooled by being contacted againstthis flat plane.

Since, with the heat sink construction described above, it must beensured that the gap between the edge portions of the open portion ofthe groove is equal to the diameter of the pipe, accordingly it has beennecessary to process the groove and the pipe at high accuracy.Furthermore there is a fear that, when the pipe is being inserted intothe groove, damage may be caused to the pipe due to contact between thesides of the pipe and the sides of the grooves. In particular, if theprocessing accuracy for the groove is bad, and the gap between theexposed edges of the groove is narrower than the diameter of the pipe,then damage will very likely be caused to the pipe while it is beinginserted into the groove due to the side surfaces of the pipe and thegroove scraping together, and, if the heat sink is used over the longterm, there is a fear that it will deteriorate over time and thatcooling fluid will leak out from it due to this damage cracking andbreaking.

Accordingly, the object of the present invention is to provide a methodof manufacturing a heat sink, and a heat sink, with which, when a pipethereof is being fitted into a groove provided in a base thereof, thereis no danger of damage being caused to the pipe due to the side surfacesof the pipe contacting the side surfaces of the groove.

SUMMARY OF THE INVENTION

In the method of manufacturing a heat sink according to the presentinvention, there are included: a first process of fitting into a groove,formed in a base and both of whose side surfaces are provided withlongitudinally extending irregular portions, such as projections orconcave portions and whose upper portion is open, from the groove openportion, a pipe that has a diameter smaller than the gap between theedge portions of the open portion of the groove; and a second process ofpressing upon the pipe from above the open portion of the groove anddeforming the upper portion of the pipe so that it follows the plane ofthe open portion of the groove, and moreover deforming both sideportions of the pipe so that they follow along the inner surfaces ofboth side portions of the groove, and thereby engaging both sideportions of the pipe with the irregular portions. A fluid may beenclosed in the interior of this pipe.

According to this type of structure, it is possible to fit the pipe intothe groove that is formed in the base without any damage occurring tothe pipe, even if the processing accuracy of the base or the pipe ispoor. Furthermore it is possible to fix the pipe in the groove withoutthe use of any adhesive or the like, since, during the process ofdeformation of the pipe both of the side surfaces of the pipe engagewith the projections or concave portions that are provided to thegroove. Moreover, by pressing the pipe while fluid is enclosed withinthe pipe, it is possible to ensure that the pressure over the entireinner surface of the pipe is equal. Due to this, it is possible todeform the pipe so that its outer circumferential surface comes intooverall contact against the entirety of both the side surfaces and alsothe bottom surface of the groove.

In an embodiment of this method of manufacturing a heat sink accordingto the present invention, the following specialization may be employed.

The second process may include: a third process of installing a guidetool that has a guide surface that guides a pressing tool along thevertical direction against the open portion of the groove; and a fourthprocess of guiding the pressing tool in the downwards direction alongthe guide surface of the guide tool that was installed by the thirdprocess, so that the upper portion of the pipe is pressed by a pressingsurface of the pressing tool, and so that thereby the upper portion ofthe pipe is deformed so as to follow the plane of the open portion ofthe groove.

And, in another embodiment of this method of manufacturing a heat sinkaccording to the present invention, the following specialization may beemployed.

There may be further included a fifth process of, after deformation bythe second process, cutting the upper portion of the pipe and/or theupper portion of the base, so that the upper portion of the pipe and theplane of the open portion of the groove substantially coincide with oneanother.

Moreover, the heat sink according to the present invention is one thatis made by any of the methods detailed above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are respectively a perspective view before assembly of abase and pipes of a heat sink manufactured by the method of manufactureof the present invention, and an enlarged partial sectional elevationview thereof;

FIG. 2 is a flow chart for explanation of this method of manufacturing aheat sink;

FIGS. 3A through 3F are sectional views showing how this heat sink isassembled;

FIGS. 4A and 4B are respectively a figure showing the general appearanceof a heat sink itself, and a figure showing the general appearance ofthis heat sink with a thermal component attached thereto; and

FIGS. 5A through 5C are sectional elevation views showing examples ofother possible constructions for the grooves.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A and 1B are respectively a perspective view of a base and pipesof a heat sink manufactured by the method of manufacture of the presentinvention before assembly, and an enlarged partial sectional elevationview thereof.

As shown in FIG. 1A, this heat sink 1 comprises a base 3, a pipe 7A, anda pipe 7B.

The base 3 is a block (a plate) made from aluminum or aluminum alloy,and is provided with grooves 5A and 5B that have exposed sides (exposedfaces) at a contacting face 3A that is contacted against a thermalcomponent 9 such as a semiconductor (for example an IGBT) or the like(refer to FIG. 4B). A pipe 7A is fitted into this groove 5A, and a pipe7B is fitted into the groove 5B. Furthermore, the groove 5A and thegroove 5B are provided in positions that contact against the bottomsurface of the thermal component 9, so that, when the thermal component9 is contacted against the contacting face 3A, it is possible to coolthe thermal component 9 with good efficiency due to the pipe 7A and thepipe 7B contacting against the bottom surface of the thermal component9. In other words, the pipes 7A and 7 are provided upon lines which aresymmetric with respect to the center line C, along the longitudinaldirection of the contacting face 3A. And their lengths are the same asthe length L of the base 3 in its short direction.

Furthermore, the contacting face 3A is wider than the bottom surface ofthe thermal component 9 (refer to FIG. 4B), and four screw holes 4A, 4B,4C, and 4D are provided near the corners of the contacting face 3A forfixing the thermal component 9.

It should be understood that, although the contacting face 3A is dividedinto the three surfaces 3A1, 3A2, and 3A2 by the grooves 5A and 5B, inthe following explanation these three surfaces will be referred togenerally as the contacting face 3A.

The pipes 7A and 7B are straight tubes made from copper whose crosssections are circular. Fluid for cooling the thermal component 9 duringuse may be enclosed in the interiors of the pipes 7A and 7B duringmanufacture; or they may be used as heat pipes in which such a fluidflows. The overall length of each of the pipes 7A and 7B is longer thanthe length L of the grooves 5A and 5B. This overall length of the pipes7A and 7B may be set to a length corresponding to the position at whichthe heat sink 1 is used or fixed.

The groove 5A and the groove 5B have the same cross sectional shape.Moreover, the pipe 7A and the pipe 7B have the same cross sectionalshape. While, for the sake of brevity, the following explanation isprincipally phrased in terms of the groove 5A and the pipe 7A, the samedescription holds for the groove 5B and the pipe 7B as well. As shown inFIG. 1B, the groove 5A is generally rectangular in cross section, andhas planar side surfaces 51A and 51B and a planar bottom surface 51C.The corner portion 51D between the side surface 51A and the bottomsurface 51C is processed to be formed as a curved surface, and similarlythe corner portion 51D between the side surface 51B and the bottomsurface 51C is processed to be formed as a curved surface. Thehorizontal plane at the portion of the groove 5A that opens to thecontacting face 3A and that is parallel to the contacting face 3A istermed the exposed surface plane 51F (in FIG. 1B, this exposed surfaceplane 51F is shown by a double dotted broken line).

Furthermore, at the upper end portions of the side surface 51A and theside surface 51B (i.e. at the portions that border upon the exposedsurface plane 51F), the cross section is formed as approximatelyletter-“λ” shaped projections 53A and 53B respectively. Theseprojections 53A and 53B are for engaging with a pipe which has beenfitted into the groove 5A and deformed. These projections 53A and 53Bare provided along the groove 5A, and their overall lengths are equal toL.

It should be understood that it is desirable for the edge portions andthe root portions of these projections 53A and 53B to be processed intoarcuate shapes. By doing this it is possible to prevent damage to themold, and to prevent the outer circumferential surface of the pipe fromsuffering damage when the pipe is deformed.

The gap between the edge portions of the open portion of the groove 5A,in other words the open width W of the groove 5A, is a little greaterthan the diameter D of the pipe 7A in its non-deformed state. Moreover,the width Y between the mutually opposing side surfaces 51A and 51B issomewhat greater than the above described open width W. Furthermore, thedepth F of the groove 5A (i.e. the distance between its exposed surfaceplane 51F and its bottom surface 51C) is somewhat less than the diameterD of the pipe 7A.

Since the groove 5A of the base 3 and the pipe 7A are set to havedimensions as described above, accordingly the pipe 7A is not abradedaway by the sides or the projections of the groove 5A when the pipe 7Ais being fitted into the groove 5A, even if the processing accuracy ofthe groove is poor and its dimensions vary somewhat.

The circumference of the pipe 7A is almost the same as the circumferenceof the groove 5A with the exposed surface plane 51F included. It shouldbe understood that, although a deformation process is performed so as tomake the two side surfaces 51A and 51B and the bottom surface 51C(collectively termed the inner surface of the groove 5A) and the outercircumferential surface of the pipe 7A generally contact against oneanother, nevertheless, depending upon the nature of the material of thepipe 7A and the exact cross sectional shape of the groove 5A, sometimesit may happen that some portion of the pipe 7A does not contact againstthe corresponding portion of the inner surface of the groove 5A. Due tothis, the circumference of the pipe 7A and the circumference of thegroove 5A with the exposed surface plane 51F included, and the crosssectional shape of the groove 5A, should be determined upon byperforming actual experiments with deformation of various test pipes 7A,so as to ensure that the upper surface of the pipe 7A after thedeformation process conforms to a planar shape that follows the exposedsurface plane 51F, and so that its side surfaces and its bottom surfacecontact as much as possible against the inner surfaces of the groove 5A.

Next, a method for manufacture (i.e. for assembly) of this heat sinkwill be explained. While here this method of manufacture is principallyexplained in terms of the groove 5A and the pipe 7A, it will be supposedthat similar processing is performed for the groove 5B and the pipe 7Bas well.

First, as described in the process chart of FIG. 2, a fluid is enclosedin the interior of the pipe 7A which is fitted into the base 3 (a stepS1). In concrete terms, a plug (not shown in the figures) is fitted intoan opening portion 7A1 at one end of the pipe 7A shown in FIG. 1A, andis able to close up that opening portion so that fluid cannot leak outtherefrom. Then a liquid such as, for example, water or oil or the like,a fine grained powder, or a gas such as air at high pressure or the likeis appropriate as the fluid that is enclosed within the pipe. If thefluid to be enclosed within the pipe is a liquid, then this liquid isflowed into the pipe, and, when the pipe is full, another plug (also notshown) is fitted into the opening portion 7A2 of the pipe at its otherend, so as to enclose the fluid within the pipe. Furthermore, if thefluid to be enclosed within the pipe is a gas, then plugs (not shown inthe figures) may be fitted into the two opening portions 7A1 and 7A2 ofthe pipe 7A, and gas may be enclosed within the pipe using a dedicatedsetup (also not shown).

Since, by enclosing the fluid within the pipe in this manner, when theouter circumferential surface of the pipe is pressed, this pressure isapplied equally to the inner surface of the pipe, accordingly it ispossible to deform the pipe so that its outer circumferential surfacecontacts entirely against both the sides of the groove and also againstits bottom surface.

It should be understood that, depending upon the nature of the materialof the pipe 7A and the exact cross sectional shape of the groove 5A,sometimes it may happen that it is possible to deform the pipe so thatits outer circumferential surface contacts entirely against both thesides of the groove and also against its bottom surface, withoutenclosing any fluid within the pipe. In such a case, the processing ofthe above step S1 in which fluid is enclosed in the pipe, and theprocessing of a step S7 described hereinafter in which this fluid isextracted from the pipe, both become unnecessary.

Next, as shown in FIGS. 3A and 3B, the pipe 7A is set into (i.e. isfitted into) the groove 5A in the base 3 (a step S2). At this time,since the width W of the groove 5A is greater than the diameter D of thepipe 7A, accordingly no damage is caused to the outer surface of thepipe 7A due to the groove 5A contacting the pipe 7A and scraping againstit.

Next, a guide tool 11A and a guide tool 11B are installed along the twoedges of the exposed surface plane 51F of the groove 5A (a step S3). Asshown in FIG. 3C, these guide tools are tools for guiding a pressingtool 13 along the vertical direction; they may be made from rolled steeland may generally have the shape of rectangular parallelepipeds, withtheir lengths being longer than or equal to the length L of the grooves5A and 5B. Moreover, the pressing tool 13 is a tool for pressing uponthe pipe 7A, and, likewise, it may be made from rolled steel and maygenerally have the shape of a rectangular parallelepiped, with itslength being longer than or equal to the length L of the grooves 5A and5B. By installing the guide tools 11A and 11B along the edges of theexposed surface plane 51F, it is possible to prevent any portion of thepipe 7A from sticking up higher than the exposed surface plane 51F andthus projecting above the contacting face 3A of the base 3, when thepipe 7A is pressed by the pressing tool 13 from the direction of theexposed surface plane 51F.

As shown in FIG. 3C, the pressing tool 13 is installed between the twoguide tools 11A and 11B (a step S4). Next, as shown in FIG. 3D, thepressing tool 13 is slid downwards along the guide tools 11A and 11B,and presses upon the pipe 7A from above the groove (a step S5). And thepipe 7A is deformed so that its upper portion becomes a surface 7A3 (seeFIG. 4) extending substantially along the exposed surface plane 51F,with its other portions contacting against the two side surfaces 51A and51B and the bottom surface 51C of the groove 5A, and with the edges ofits upper portion being engaged by the projections 53A and 53B.

It should be understood that the pressing tool 13 is not limited tohaving a shape as shown in FIG. 13; for example, it would also beacceptable for it to be shiftable along the guide tools 11A and 11B andto have a roller shaped pressing surface. If the length L of the base 3is very long so that a plurality of thermal components 9 may be fittedthereto, then it may become difficult to deform the entire pipe 7A inone operation with a pressing tool 13 that is formed out of rolled steelin the shape of a rectangular parallelepiped. In this type of case, itis possible to deform the entire pipe 7A so as to shape its upper plane7A3 to extend substantially along the exposed surface plane 51F of thegroove 5A, by pressing a roller shaped pressing tool (not shown) uponthe pipe 7A while shifting that pressing tool along the guide tools 11Aand 11B.

When the deformation of the pipe 7A has been completed, the guide tools11A and 11B and the pressing tool 13 are removed (a step S6). And theplugs that were fitted into both the ends of the pipe 7A are removed,and the fluid within the pipe 7A is extracted (a step S7). The pipe 7Adoes not come out from within the groove 5A, since it has become engagedwith the projections 53A and 53B due to the deformation process of thestep S5.

According to the dimensions and shapes of the groove 5A and the pipe 7Aand the relationship between them, and depending upon the pressureapplied in the step S5, sometimes it may happen that the pipe 7A may,after the process of deformation, come to be in a state in which itsupper plane surface 7A3 bulges out somewhat above the exposed surfaceplane 51F, as shown in FIG. 3E. Furthermore sometimes it may happenthat, after the process of deformation, the pipe 7A may come to be in astate in which its upper plane surface 7A3 is substantially lower thanthe exposed surface plane 51F, i.e. is fully within the groove 5A, asshown in FIG. 3F. In other words, sometimes it may happen that the plane7A3 of the finished pipe 7A, the plane 7B3 of the finished pipe 7B, andthe contacting face 3A of the base 3 are not coplanar. In this type ofcase, a cutting process is performed upon at least one of the pipe 7A or7B, or the contacting face 3A of the base 3, so as to form the plane 7A3of the finished pipe 7A, the plane 7B3 of the finished pipe 7B, and thecontacting face 3A of the base 3 to be coplanar (a step S8).

When, as shown in FIG. 3E, the pipe 7A is in a state in which its upperplane surface 7A3 bulges out somewhat above the exposed surface plane51F, it is appropriate for mainly the pipe 7A to be cut down. On theother hand when, as shown in FIG. 3F, the pipe 7A is in a state in whichits upper plane surface 7A3 is substantially lower than the exposedsurface plane 51F, then it is appropriate for mainly the contacting face3A of the base 3 to be cut down. By performing a cutting process in thismanner, it is possible to ensure that the plane 7A3 of the finished pipe7A, the plane 7B3 of the finished pipe 7B, and the contacting face 3A ofthe base 3 become coplanar. By performing processing upon the uppersurface of the heat sink in this manner to ensure that it is planar, itis possible to make it closely conform to the bottom surface of thethermal component 9, and thus it is possible reliably to cool thethermal component 9.

It should be understood that, if the pipe 7A is to be cut, then it isnecessary to use a pipe of thickness sufficiently greater than theamount to be cut away, in order to ensure that no holes open up in thepipe after it has been cut. Furthermore, if in the step S5 the plane 7A3of the pipe 7A, the plane 7B3 of the pipe 7B, and the contacting face 3Aof the base 3 are already finished as coplanar, then no further cuttingprocess such as the step S8 will be necessary.

When the above described processes of deforming and (possibly) cuttingthe pipe 7A and the pipe 7B have been completed, the manufacture of theheat sink 1 is finished, as shown in FIG. 4A.

When the heat sink 1 is to be used, it will be sufficient to contact thebottom surface of a thermal component 9 (for example an IGBT module, asshown in the figure) against the upper surface of the heat sink 1 (i.e.against the contacting face 3A of the base 3), as shown in FIG. 4B, andto fix screws 10A through 10D into the screw holes 4A through 4D.

If only one of these heat sinks 1 is to be used, then the openingportion 7A1 of the pipe 7A and the opening portion 7B1 of the pipe 7Bare connected together with a joining pipe (not shown in the figures).Moreover, the opening portion 7A2 of the pipe 7A and the opening portion7B2 of the pipe 7B are connected to a pump (not shown in the figures),via joining conduits (not shown in the figures) or directly, so thatfluid may be circulated by the pump through the interiors of the pipes7A and 7B, thus cooling the thermal component 9.

Furthermore, if a plurality of these heat sinks 1 are to be used, thenthe opening portions of the pipes 7A and 7B of these heat sinks 1 areconnected in sequence with joining conduits, not shown in the figures.And two of them are connected to a pump. Thus, fluid may be circulatedby the pump through the interiors of the pipes 7A and 7B of each of theheat sinks 1, thus cooling the thermal component or components 9 thatare attached to these heat sinks 1. Furthermore it would also bepossible further to increase the length of the heat sink 1, so as toattach a plurality of thermal components 9 to this single heat sink 1for being cooled.

Next, with regard to the position of the projections 53A and 53B whichare provided upon the side surfaces 51A and 51B of the groove 5A that isprovided in the base 3, the positions shown in FIGS. 1 and 3 are not tobe considered as being limitative of the present invention; otherpositions for these projections may be employed, provided that theprojections are able to engage properly with the pipe 7A. For example inan alternative structure, as shown in FIG. 5A, it would be possible toprovide projections 53A2 and 53B2 in positions that are lower than theupper edge portions of the side surfaces 51A2 and 51B2 of the groove5A2, in other words in positions that do not touch the exposed surfaceplane 51F2. At this time, the cross sectional shapes of theseprojections may be processed into shapes whose edges are smooth, forexample into tear shapes or into arcuate shapes. Since, by providing theprojections 53A2 and 53B2 in positions as described above, theseprojections bite into the pipe 7A when the pipe 7A has been deformed,accordingly it is possible for the pipe 7A to be reliably embeddedwithin the groove 5A2 and held.

Furthermore, it would also be possible to arrange to provide concaveportions on the side surfaces of the groove, rather than projections.Such concave portions should be provided at positions upon the sidesurfaces of the grooves that are lower than their upper edge portions,in other words at positions that do not contact the exposed surfaceplane of the groove. For example it is possible, as shown in FIG. 5B, toprovide a concave portion 53A3 and a concave portion 53B3 at respectiveintermediate portions upon the side surface 51A3 and the side surface51B3 of the groove 5A3. Moreover it is possible, as shown in FIG. 5C, toprovide a concave portion 53A4 and a concave portion 53B4 at therespective lower edge portions of the side surface 51A4 and the sidesurface 51B4 of the groove 5A4 (i.e. at the portions where these sidesurfaces abut against the bottom surface 51C). Since, by providing suchconcave portions upon the side surfaces of the groove, correspondingportions of the pipe are forced into these concave portions when thepipe is deformed, accordingly the pipe 7A is engaged within the grooveby these corresponding portions projecting into and engaging with theconcave portions. Accordingly, it is possible reliably to embed and holdthe pipe 7A within the groove 5A3 or the groove 5A4.

It would also be acceptable to arrange to provide the projections orconcave portions shown in FIG. 5 intermittently along the depthdirection of the groove. By forming the projections or concave portionsin this type of shape, it is possible reliably to prevent the pipe 7Afrom deviating in the direction of the side surface 3S1 or the sidesurface 3S2 of the base 3.

It should be understood that it is desirable to process the edges and/orbase root portions of the projections or the concave portions intoarcuate shapes. By doing this it is possible to prevent damage to themold, and to prevent the outer circumferential surface of the pipe fromsuffering damage when the pipe is deformed.

It should be understood that, even if the groove provided in the base 3has a shape as shown in FIG. 5, as explained on the basis of FIG. 1B,still, as seen from the side of the exposed surface plane (i.e. from theside of the contacting face 3A), the opening width W between the twosides of the upper portion of the groove (i.e. the gap between theprojections 53A2 and 53B2, or between the side surface 51A3 and the sidesurface 51B3, or between the side surface 51A4 and the side surface51B4) is greater than the diameter D of the pipe 7A. Moreover, the widthY between the side surface 51A2 and the side surface 51B2 with theprojections 53A2 and 53B2 excluded, or the width X between the twoconcave portions (i.e. between the concave portion 53A3 and the concaveportion 53B3, or between the concave portion 53A4 and the concaveportion 53B4), is greater than the above described opening width W.Furthermore, the depth F of the groove 5A (i.e. the distance between itsexposed surface plane 51F and its bottom surface 51C) is shorter thanthe diameter D of the pipe 7A.

Yet further, the circumference of the pipe 7A and the circumference ofthe groove with its exposed surface plane included, and the crosssectional shape of the groove, should be determined upon by performingactual experiments with deformation of various test pipes 7A, so as toensure that the upper surface of the pipe 7A after the deformationprocess conforms to a planar shape that follows the exposed surfaceplane 51F, and so that its side surfaces and its bottom surface contactas much as possible against the inner surfaces of the groove 5A.

It should be understood that while, in the above explanation, astructure was described in which two pipes were embedded in the base,this is not to be considered as limitative of the present invention; itis also possible to utilize a single such pipe, or more than two suchpipes, provided that it is possible to contact that pipe or pipesagainst the bottom surface of the thermal component with good efficiencyso as to cool it well.

Furthermore, with regard to the materials from which the base, thepipes, the guide tools, and the pressing tool are made, it would also beacceptable to utilize other materials, provided that it is possible todeform the pipes with good efficiency, and that it is possible to coolthe thermal component with good efficiency.

1. A method of manufacturing a heat sink in which a heat sink ismanufactured by fitting a pipe into a groove formed in a base,comprising: a first process of fitting into a groove, formed in a baseand both of whose side surfaces are provided with longitudinallyextending irregular portions and whose upper portion is open, from saidgroove open portion, a pipe that has a diameter smaller than the gapbetween the edge portions of said open portion of said groove; and asecond process of pressing upon said pipe from above said open portionof said groove and deforming the upper portion of said pipe so that itfollows the plane of said open portion of said groove, and moreoverdeforming both side portions of said is pipe so that they follow alongthe inner surfaces of both side portions of said groove, and therebyengaging both side portions of said pipe with said irregular portions.2. A method of manufacturing a heat sink according to claim 1, whereinsaid irregular portions are projections.
 3. A method of manufacturing aheat sink according to claim 1, wherein said irregular portions areconcave portions.
 4. A method of manufacturing a heat sink according toclaim 1, wherein, in said first process, a fluid is enclosed in saidpipe.
 5. A method of manufacturing a heat sink according to claim 1,wherein said second process comprises: a third process of installing aguide tool that has a guide surface that guides a pressing tool alongthe vertical direction against said open portion of said groove; and afourth process of guiding said pressing tool in the downwards directionalong said guide surface of said guide tool that was installed by saidthird process, so that said upper portion of said pipe is pressed by apressing surface of said pressing tool, and thereby said upper portionof said pipe is deformed so as to follow said plane of said open portionof said groove.
 6. A method of manufacturing a heat sink according toclaim 1, further comprising a fifth process of, after deformation bysaid second process, cutting said upper portion of said pipe and/or theupper portion of said base, so that said upper portion of said pipe andsaid plane of said open portion of said groove substantially coincidewith one another.
 7. A method of manufacturing a heat sink according toclaim 1, wherein said projections or concave portions are provided atpositions on said side surfaces of said groove that do not contact itssaid open portion.
 8. A heat sink manufactured by the method of claim 1.9. A heat sink manufactured by the method of claim
 2. 10. A heat sinkmanufactured by the method of claim
 3. 11. A heat sink manufactured bythe method of claim 4.